JP6659887B2 - Diagnostic device and diagnostic method - Google Patents

Description

  The present invention relates to a diagnostic device and a diagnostic method.

  Conventionally, a flying capacitor type battery monitoring system in which the voltage of a battery is charged to a capacitor, the battery is separated from the capacitor, and the voltage of the capacitor is detected by a voltage detection circuit in that state to measure the battery voltage indirectly. Devices are known.

  In the above-mentioned flying capacitor type battery monitoring device, it is known to perform failure diagnosis of a switch for switching connection between a capacitor and a voltage detection circuit. For example, in Patent Literature 1, when a voltage detection circuit detects a voltage in spite of giving an off command to a switch for switching connection between a capacitor and a voltage detection circuit, it is determined that the switch has a short-circuit failure. .

JP 2014-182089 A

  In the above-described battery monitoring device, the battery whose voltage is to be detected is also used as a power supply for diagnosis, so that the reliability of diagnosis depends on the battery.

  An object of the present invention, which has been made in view of such a viewpoint, is to provide a diagnostic device and a diagnostic method capable of diagnosing a state of a flying capacitor or a switch without depending on a battery whose voltage is to be detected.

In order to solve the above-mentioned problems, a diagnostic device according to a first aspect includes:
A capacitor connectable in parallel to each first battery of the plurality of first batteries connected in series;
A plurality of first switches for switching a connection state between the plurality of first batteries and the capacitor;
A detection circuit that detects a potential difference between both terminals of the capacitor, or detects a discharge current from the capacitor,
A second switch for switching a connection state between the capacitor and the detection circuit;
A changeover switch for switching a connection state between the second battery different from the first battery and the capacitor;
A control unit that controls the first switch, the second switch, and the changeover switch;
The capacitor, a lowermost first switch connected to the ground among the plurality of first switches, and a diagnostic unit that diagnoses at least one of the second switch,
After the control unit turns on the changeover switch and applies a voltage from the second battery to the capacitor, the detection circuit detects a potential difference or a discharge current,
The diagnostic unit diagnoses at least one of the capacitor, the lowermost first switch, and the second switch.

In order to solve the above-mentioned problems, a diagnostic method according to a second aspect includes:
A capacitor that can be connected in parallel to each first battery of the plurality of first batteries connected in series, a plurality of first switches that switch a connection state between the plurality of first batteries and the capacitor, and both terminals of the capacitor A detection circuit that detects a potential difference between the two or a discharge current from the capacitor, a second switch that switches a connection state between the capacitor and the detection circuit, and a second battery that is different from the first battery. A changeover switch for switching a connection state with the capacitor, and a diagnostic method in a diagnostic device including:
Turning on the switch, applying a voltage from the second battery to the capacitor, the detection circuit detects a potential difference or a discharge current,
Diagnosing at least one of the capacitor, a lowermost first switch connected to the ground among the plurality of first switches, and the second switch.

In order to solve the above-described problems, a diagnostic device according to a third aspect includes:
A detection circuit for detecting voltage or current;
A connection circuit for detection capable of connecting a first battery to the detection circuit;
A diagnostic connection circuit capable of connecting a power supply different from the first battery to the detection connection circuit;
A diagnostic unit for diagnosing the connection circuit for detection by connecting the connection circuit for diagnosis to the connection circuit for detection.

  According to the diagnostic device of the first aspect, the state of the flying capacitor or the switch can be diagnosed without depending on the battery whose voltage is to be detected.

  According to the diagnostic method of the second aspect, the state of the flying capacitor or the switch can be diagnosed without depending on the battery whose voltage is to be detected.

  According to the diagnostic device of the third aspect, the state of the flying capacitor or the switch can be diagnosed without depending on the battery whose voltage is to be detected.

It is a block diagram showing the example of composition of the diagnostic device concerning one embodiment. FIG. 2 is a block diagram illustrating an example of a configuration of a constant voltage circuit in FIG. 1. 5 is a flowchart illustrating an example of a procedure of a diagnostic method by the diagnostic device according to the embodiment. It is a block diagram for explaining diagnosis 1-1. It is a block diagram for explaining diagnosis 1-2. It is a figure showing a timing chart of diagnosis 1-2. FIG. 7 is a block diagram for explaining diagnosis 2. FIG. 9 is a diagram showing a timing chart of diagnosis 2; It is a block diagram for explaining diagnosis 3-1. It is a figure showing the timing chart of diagnosis 3-1. It is a block diagram for explaining diagnosis 3-2. It is a figure showing the timing chart of diagnosis 3-2. It is a block diagram for explaining diagnosis 3-3. It is a figure showing the timing chart of diagnosis 3-3. It is a block diagram for explaining diagnosis 3-4. It is a figure showing the timing chart of diagnosis 3-4. It is a block diagram for explaining diagnosis 3-5. It is a figure showing the timing chart of diagnosis 3-5. It is a block diagram for explaining diagnosis 3-6. It is a figure showing a timing chart of diagnosis 3-6. It is a block diagram for explaining diagnosis 3-7. It is a figure showing the timing chart of diagnosis 3-7. FIG. 4 is a block diagram for explaining diagnosis 4. FIG. 9 is a diagram showing a timing chart of diagnosis 4. 4 is a flowchart illustrating an example of a detailed procedure of steps S3 and S4 in FIG. 4 is a flowchart illustrating an example of a detailed procedure of steps S3 and S4 in FIG. 4 is a flowchart illustrating an example of a detailed procedure of steps S3 and S4 in FIG.

  Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

  As shown in FIG. 1, the diagnostic device 100 according to one embodiment is connected to first batteries 200A to 200E. The diagnostic device 100 and the first batteries 200A to 200E may be mounted on a vehicle such as a vehicle equipped with an internal combustion engine such as a gasoline engine or a diesel engine, or a hybrid vehicle capable of running with the power of both an internal combustion engine and an electric motor. .

  The first batteries 200A to 200E may be included in a battery pack. The battery pack may include the diagnostic device 100. The battery pack may include a BMS (Battery Management System). The diagnostic device 100 may function as a BMS or may be included in the BMS.

  In the example shown in FIG. 1, a first battery 200A, a first battery 200B, a first battery 200C, a first battery 200D, and a first battery 200E are connected in series. Hereinafter, the first batteries 200 </ b> A to 200 </ b> E may be collectively referred to as the first batteries 200 unless it is particularly necessary to distinguish them.

  In the example illustrated in FIG. 1, five first batteries 200 are connected in series, but the number of the first batteries 200 is not limited to this. Any number of the first batteries 200 may be connected in series.

  The first battery 200 may be a secondary battery having a wide SOC (State Of Charge) bandwidth. The SOC bandwidth of the first battery 200 may be, for example, 10 to 90%. The first battery 200 is, for example, a lithium ion battery or a nickel hydride battery, but is not limited thereto, and may be another secondary battery.

  The diagnostic device 100 includes first switches 1A to 1K, second switches 2A and 2B, a fourth switch 4, a capacitor 10, a resistor 11, a detection circuit 20, a constant voltage circuit 30, a capacitor voltage detection circuit 40, a sub-detection circuit 50, a control unit 60, and a storage unit 70.

  The capacitor 10 can be connected in parallel to the first batteries 200A to 200E via the first switches 1A to 1K. The capacitor 10 can be charged by the power supplied from the first battery 200. The detection circuit 20 can detect a potential difference between both terminals of the capacitor 10 charged by the first battery 200. That is, the capacitor 10 functions as a flying capacitor in a flying capacitor type voltage measurement.

  The first switches 1A to 1K switch the connection state between the first battery 200 and the capacitor 10 according to a command from the control unit 60. When the first switches 1A to 1K are controlled to be turned on, both ends thereof conduct. When the first switches 1A to 1K are controlled to be turned off, both ends are insulated. In FIG. 1, control lines from the control unit 60 to the first switches 1A to 1K are omitted to improve readability.

  The first switch 1A, the first switch 1C, the first switch 1E, the first switch 1G, and the first switch 1J are respectively a first battery 200A, a first battery 200B, a first battery 200C, a first battery 200D, and a first battery 200D. The connection state between the positive electrode of battery 200E and first node 10A is switched. The first node 10A is a node connected to one end of the capacitor 10.

  The first switch 1B, the first switch 1D, the first switch 1F, the first switch 1H, and the first switch 1K are respectively a first battery 200A, a first battery 200B, a first battery 200C, a first battery 200D, and a first battery 200D. The connection state between the negative electrode of the battery 200E and the second node 10B is switched. The second node 10B is a node connected to the other end of the capacitor 10.

  Hereinafter, the first switches 1 </ b> A to 1 </ b> K may be collectively referred to as a first switch 1 unless it is particularly necessary to distinguish them. The first switch 1 may be a mechanical switch having a movable part. The first switch 1 has a contact and may be configured to switch between a conductive state and an insulated state by opening and closing the contact. The first switch 1 may be, for example, an electromagnetic relay.

  The second switches 2A and 2B switch the connection state between the capacitor 10, the detection circuit 20, and the sub-detection circuit 50 according to a command from the control unit 60. When the second switches 2A and 2B are controlled to be turned on, both ends thereof conduct. When the second switches 2A and 2B are controlled to be turned off, both ends are insulated. In FIG. 1, control lines from the control unit 60 to the second switches 2A and 2B are omitted to improve readability.

  The second switch 2A switches the connection state between the first node 10A, the detection circuit 20, and the sub-detection circuit 50. The second switch 2B switches the connection state between the second node 10B and the ground. The second switch 2A is also referred to as an upper second switch. The second switch 2B is also referred to as a lower second switch.

  Hereinafter, the second switches 2 </ b> A and 2 </ b> B may be collectively referred to as a second switch 2 unless it is particularly necessary to distinguish them. The second switch 2 may be a mechanical switch having a movable part. The second switch 2 may have a contact, and may be configured to switch between a conductive state and an insulated state by opening and closing the contact. The second switch 2 may be, for example, an electromagnetic relay.

  The fourth switch 4 switches a connection state between the first node 10A and the resistor 11 according to a command from the control unit 60. When the fourth switch 4 is controlled to be turned on, both ends thereof conduct. When the fourth switch 4 is controlled to be turned off, both ends are insulated. The fourth switch 4 may be a mechanical switch having a movable part. The fourth switch 4 has a contact, and may be configured to switch between a conductive state and an insulated state by opening and closing the contact. The fourth switch 4 may be, for example, an electromagnetic relay. In FIG. 1, a control line from the control unit 60 to the fourth switch 4 is omitted to improve readability.

  The resistor 11 has one end connected to the fourth switch 4 and the other end grounded. The fourth switch 4 is normally controlled to be off. When the fourth switch 4 is turned on, the capacitor 10 discharges via the resistor 11. That is, the fourth switch 4 and the resistor 11 constitute a discharge circuit for discharging the charge charged in the capacitor 10.

  The detection circuit 20 can detect a potential difference between both terminals of the capacitor 10 when the second switch 2 is on. The detection circuit 20 includes an operational amplifier 21 and an AD converter 22.

  The operational amplifier 21 has a negative input terminal and an output terminal connected to form a voltage follower. The voltage follower including the operational amplifier 21 functions as a buffer, and outputs the voltage input to the detection circuit 20 to the AD converter 22.

  It is to be noted that the voltage follower including the operational amplifier 21 is disposed in a stage preceding the AD converter 22, and the configuration of the detection circuit 20 is not limited to this. Instead of a voltage follower, an amplifier having an amplification factor different from 1 may be arranged in a stage preceding the AD converter 22.

  The AD converter 22 has an AD input terminal 22A. The AD converter 22 converts an analog voltage input from the voltage follower including the operational amplifier 21 to the AD input terminal 22A into a digital signal corresponding to the analog voltage, and outputs the digital signal to the control unit 60.

  The AD converter 22 further has AD input terminals 22B and 22C. The AD input terminal 22B is connected to the first node 10A via the third switch 3A and the resistor 41. The AD input terminal 22B is grounded via the resistor 42. The AD input terminal 22C is connected to the second node 10B via the third switch 3B and the resistor 43. The AD input terminal 22C is grounded via the resistor 44.

  The AD converter 22 converts the analog voltage input to the AD input terminal 22B into a digital signal corresponding to the analog voltage and outputs the digital signal to the control unit 60. The AD converter 22 converts the analog voltage input to the AD input terminal 22C into a digital signal corresponding to the analog voltage, and outputs the digital signal to the control unit 60.

  The constant voltage circuit 30 has a control terminal 30A and an output terminal 30B. The constant voltage circuit 30 outputs a constant voltage from the output terminal 30B according to a control signal input from the control unit 60 to the control terminal 30A. The constant voltage circuit 30 can output a constant voltage to the capacitor 10. In the present embodiment, the constant voltage circuit 30 outputs a constant voltage when a high signal is input to the control terminal 30A from the control unit 60, and stops outputting a constant voltage when a low signal is input. I do.

  FIG. 2 shows an example of the configuration of the constant voltage circuit 30. The constant voltage circuit 30 has a power supply terminal 30C not shown in FIG. 1 in addition to the control terminal 30A and the output terminal 30B.

  The constant voltage circuit 30 receives a power supply voltage from a power supply terminal 30C. As shown in FIG. 2, the constant voltage circuit 30 receives a power supply voltage from a second battery 300 to a power supply terminal 30C via a voltage conversion circuit 400, for example.

  The second battery 300 is different from the first battery 200. The second battery 300 may be a secondary battery having a narrower SOC bandwidth than the first battery 200. The second battery 300 is, for example, a lead storage battery, but is not limited thereto, and may be another secondary battery. Although not particularly shown, the second battery 300 is connected in parallel with the first battery 200, and supplies power to auxiliary equipment of the vehicle.

  The voltage conversion circuit 400 converts the voltage supplied from the second battery 300 and supplies the voltage to the power supply terminal 30C of the constant voltage circuit 30. The voltage conversion circuit 400, for example, reduces the voltage of 12V supplied from the second battery 300 to 5V and supplies it to the power supply terminal 30C of the constant voltage circuit 30.

  As shown in FIG. 2, the constant voltage circuit 30 includes an NPN transistor 31, a PNP transistor 32, a capacitor 33, and resistors 34 to 38.

  When the control terminal 30A of the constant voltage circuit 30 receives a high signal from the control unit 60, the base voltage of the NPN transistor 31 increases, and the NPN transistor 31 turns on. When the NPN transistor 31 turns on, the base voltage of the PNP transistor 32 decreases, and the PNP transistor 32 turns on. When the PNP transistor 32 is turned on, a current can be supplied from the output terminal 30B to the first node 10A. For example, when the second switch 2B shown in FIG. 1 is on, the capacitor 10 can be charged by the current supplied from the output terminal 30B of the constant voltage circuit 30. At this time, a constant voltage lower than the power supply voltage input to the power supply terminal 30C by the voltage drop by the resistor 34 and the PNP transistor 32 is supplied to the output terminal 30B of the constant voltage circuit 30. As described above, the PNP transistor 32 can function as a changeover switch that switches the connection state between the second battery 300 and the capacitor 10 according to a command from the control unit 60. When the PNP transistor 32 is turned on, the voltage from the second battery 300 can be applied to the capacitor 10.

  As described above, the constant voltage circuit 30 generates a constant voltage based on the power supply voltage supplied from the secondary battery 300 having a narrow SOC bandwidth, for example, a lead storage battery. Thus, the constant voltage circuit 30 can stably generate a constant voltage equal to or larger than a predetermined value.

  The constant voltage output by the constant voltage circuit 30 is the maximum voltage that can be supplied by the first batteries 200A to 200E connected in series, that is, the positive terminal of the first battery 200A and the negative terminal of the first battery 200E. May be smaller than the voltage between the two. For example, when the maximum voltage that can be supplied by each first battery 200 is 2.4 V, the maximum voltage that can be supplied by the first batteries 200A to 200E connected in series is 12V. In this case, the constant voltage output from the constant voltage circuit 30 can be smaller than 12V. Thus, when the constant voltage output from the constant voltage circuit 30 is input to the operational amplifier 21 of the detection circuit 20, the possibility that the operational amplifier 21 may be reduced can be reduced.

  The constant voltage output by the constant voltage circuit 30 may be higher than the maximum voltage that can be supplied by each first battery 200. For example, when the maximum voltage that can be supplied by each first battery 200 is 2.4 V, the constant voltage output by the constant voltage circuit 30 may be higher than 2.4 V. Accordingly, when detecting the voltage charged in the capacitor 10 from the constant voltage circuit 30 in the diagnostic processing, the control unit 60 can confirm that the voltage is not the voltage supplied from the first battery 200.

  The diagnostic device 100 can perform failure diagnosis using the constant voltage output from the constant voltage circuit 30. If the voltage of the first battery 200 to be detected is used as the reference voltage when the diagnostic device 100 performs the failure diagnosis, if the battery capacity of the first battery 200 is reduced, Failures such as the first switch 1 and the second switch 2 may not be correctly detected. However, since the diagnostic device 100 according to the present embodiment performs the failure diagnosis using the constant voltage output from the constant voltage circuit 30, the diagnostic device 100 does not depend on the first battery 200, and does not depend on the first battery 200. The state of the two switches 2 and the like can be diagnosed.

  Description will be made again with reference to FIG.

  The capacitor voltage detection circuit 40 is a circuit for detecting the voltage of both terminals of the capacitor 10, that is, the voltages of the first node 10A and the second node 10B without using the operational amplifier 21 of the detection circuit 20.

  The capacitor voltage detection circuit 40 includes the third switches 3A and 3B, a resistor 41, a resistor 42, a resistor 43, and a resistor 44.

  The third switch 3A switches a connection state between the first node 10A and the resistor 41 according to a command from the control unit 60. The third switch 3B switches a connection state between the second node 10B and the resistor 43 according to a command from the control unit 60. When the third switches 3A and 3B are controlled to be turned on, both ends thereof conduct. When the third switches 3A and 3B are controlled to be turned off, both ends thereof are insulated. In FIG. 1, the control lines from the control unit 60 to the third switches 3A and 3B are omitted to improve readability.

  Hereinafter, the third switches 3A and 3B may be collectively referred to as a third switch 3 when there is no particular need to distinguish them. The third switch 3 may be a mechanical switch having a movable part. The third switch 3 may have a contact, and may be configured to switch between a conductive state and an insulated state by opening and closing the contact. The third switch 3 may be, for example, an electromagnetic relay.

  The resistor 41 is connected at one end to the first node 10A via the third switch 3A. The other end of the resistor 41 is connected to the AD input terminal 22 </ b> B of the AD converter 22 and the resistor 42.

  The resistor 42 has one end connected to the AD input terminal 22B of the AD converter 22 and the resistor 41. The resistor 42 is grounded at the other end.

  The resistor 43 has one end connected to the second node 10B via the third switch 3B. The resistor 43 has the other end connected to the AD input terminal 22C of the AD converter 22 and the resistor 44.

  The resistor 44 has one end connected to the AD input terminal 22C of the AD converter 22 and the resistor 43. The resistor 44 is grounded at the other end.

  When the constant voltage circuit 30 is off and the third switch 3A is on, one of the first switch 1A, the first switch 1C, the first switch 1E, the first switch 1G, and the first switch 1J turns on. Then, the voltage on the positive electrode side of the first battery 200 connected to the first switch 1 that is turned on is supplied to the AD input terminal 22B of the AD converter 22.

  When the constant voltage circuit 30 is off and the third switch 3A is on, the first switch 1A, the first switch 1C, the first switch 1E, the first switch 1G, and the first switch 1J are all off. Then, 0 V is supplied to the AD input terminal 22B of the AD converter 22 via the grounded resistor 42.

  When the constant voltage circuit 30 is off and the third switch 3B is on, if any one of the first switch 1B, the first switch 1D, the first switch 1F, and the first switch 1H is on, the on state is turned on. The voltage on the negative electrode side of the first battery 200 connected to the first switch 1 is supplied to the AD input terminal 22C of the AD converter 22.

  When the constant voltage circuit 30 is off and the third switch 3B is on, if the first switch 1B, the first switch 1D, the first switch 1F, and the first switch 1H are all off, they are grounded. 0V is supplied to the AD input terminal 22C of the AD converter 22 via the resistor 44.

  When the third switch 3A is off, 0V is supplied to the AD input terminal 22B of the AD converter 22 via the resistor 42 which is grounded. When the third switch 3B is off, 0 V is supplied to the AD input terminal 22C of the AD converter 22 via the resistor 44 that is grounded.

  The sub-detection circuit 50 can detect a potential difference between both terminals of the capacitor 10 when the second switch 2 is on. The sub-detection circuit 50 is a circuit for diagnosing whether the operational amplifier 21 of the detection circuit 20 is operating normally. The sub-detection circuit 50 is controlled by the control unit 60 so as to be normally turned off.

  The sub detection circuit 50 includes an operational amplifier 51 and an AD converter 52.

  In the operational amplifier 51, the negative input terminal and the output terminal are connected to form a voltage follower. The voltage follower including the operational amplifier 51 functions as a buffer and outputs the voltage input to the sub detection circuit 50 to the AD converter 52.

  The AD converter 52 converts an analog voltage input from the voltage follower including the operational amplifier 51 into a digital signal corresponding to the analog voltage and outputs the digital signal to the control unit 60.

  FIG. 1 shows a configuration in which the AD converter 52 is an AD converter different from the AD converter 22. However, this configuration is an example, and the AD converter 22 may also have the function of the AD converter 52. In this case, the operational amplifier 51 outputs a digital signal to the AD converter 22.

  The control unit 60 is communicably connected to each component of the diagnostic device 100 by wired or wireless communication. The control unit 60 may output a control instruction to each component, or acquire information from each component.

  The control unit 60 controls on / off of the first switch 1, the second switch 2, the third switch 3, and the fourth switch 4. The control unit 60 controls on / off of the constant voltage circuit 30. When the control unit 60 turns on the constant voltage circuit 30, the constant voltage circuit 30 can supply a constant voltage to the first node 10A.

  The control unit 60 can acquire a digital signal corresponding to the analog voltage input to the AD input terminals 22A, 22B, and 22C from the AD converter 22 of the detection circuit 20. The control unit 60 can obtain a digital signal corresponding to the analog voltage input to the sub detection circuit 50 from the AD converter 52 of the sub detection circuit 50.

  The control unit 60 may be configured by a processor such as a CPU (Central Processing Unit) that executes a program defining a control procedure. When the diagnostic device 100 is mounted on a vehicle, the control unit 60 may be configured as an ECU (Electric Control Unit or Engine Control Unit) of the vehicle.

  The storage unit 70 is connected to the control unit 60 and stores information acquired from the control unit 60. The storage unit 70 may function as a working memory of the control unit 60. The storage unit 70 may store a program executed by the control unit 60. The storage unit 70 is configured by, for example, a semiconductor memory, but is not limited thereto, and may be configured by a magnetic storage medium or may be configured by another storage medium. The storage unit 70 may be included as a part of the control unit 60.

  In the present embodiment, the first switch 1, the capacitor 10, and the second switch 2A can function as a detection connection circuit that enables the first battery 200 to be connected to the detection circuit 20. In addition, the constant voltage circuit 30 can function as a diagnostic connection circuit that enables the second battery 300 to be connected to the detection connection circuit.

  The control unit 60 of the diagnostic device 100 can diagnose components in the diagnostic device 100 according to the procedure shown in the flowchart of FIG. The control unit 60 can diagnose whether a failure has occurred in the first switch 1, the second switch 2, the capacitor 10, and the operational amplifier 21.

  The control unit 60 first performs a diagnosis mainly using the capacitor voltage detection circuit 40 (step S1). In step S1, the control unit 60 diagnoses the first switches 1 other than the first switch 1K, that is, the first switch 1 at the lowest stage connected to the ground, that is, the first switches 1A to 1J. Hereinafter, the diagnosis in step S1 of the control unit 60 is referred to as “diagnosis 1”.

  Subsequently, the control unit 60 performs a diagnosis mainly using the detection circuit 20 (step S2). The control unit 60 diagnoses the lowermost first switch 1K in step S2. Hereinafter, the diagnosis in step S2 of the control unit 60 is referred to as “diagnosis 2”.

  Subsequently, the control unit 60 performs a diagnosis mainly using the constant voltage circuit 30 (step S3). The control unit 60 diagnoses the capacitor 10, the second switch 2, the operational amplifier 21, and the lowermost first switch 1K in step S3. Hereinafter, the diagnosis in step S3 of the control unit 60 is referred to as “diagnosis 3”.

  Subsequently, the control unit 60 performs a diagnosis mainly using the sub-detection circuit 50 (Step S4). The control unit 60 diagnoses the operational amplifier 21 in step S4. Hereinafter, the diagnosis in step S4 of the control unit 60 is referred to as “diagnosis 4”.

  If the control unit 60 determines that a failure has occurred in any of the components of the diagnostic device 100 at any stage of the diagnosis 1 to the diagnosis 4, the control unit 60 sets a failure flag and stops the subsequent diagnosis processing. You may.

  In the present embodiment, the control unit 60 controls on / off of the first switch 1, the second switch 2, the third switch 3, the fourth switch 4, and the constant voltage circuit 30, and the first switch 1, The description will be made assuming that both the diagnosis of the two switches 2, the capacitor 10, and the operational amplifier 21 are performed, but the present invention is not limited to this configuration. For example, the processor may include the control unit 60 and the diagnostic unit. In this case, the control unit 60 executes on / off control of the first switch 1, the second switch 2, the third switch 3, the fourth switch 4, and the constant voltage circuit 30, and the diagnostic unit executes the first switch Diagnosis and the like for the first, second switch 2, capacitor 10, and operational amplifier 21 may be executed.

  Hereinafter, the details of the diagnosis 1 to the diagnosis 4 will be described.

[Diagnosis 1]
Diagnosis 1 includes the following two diagnoses.
Diagnosis 1-1: Short fault diagnosis of first switches 1A to 1J ・ Diagnosis 1-2: Open fault diagnosis of first switches 1A to 1J

(Diagnosis 1-1)
The diagnosis 1-1 is a short-circuit failure diagnosis of the first switches 1A to 1J other than the lowermost first switch 1K. The diagnosis 1-1 will be described with reference to the block diagram shown in FIG. In FIG. 4, some of the components of the diagnostic device 100 shown in FIG.

  In diagnosis 1-1, the control unit 60 controls the first switch 1 to be off, the second switch 2 to be off, and the third switch 3 to be on. The control unit 60 controls the constant voltage circuit 30 shown in FIG. 1 to be turned off.

  At this time, if any one of the first switches 1A to 1J has a short-circuit failure, the AD converter 22 connects to the first switch 1 having the short-circuit failure at one of the AD input terminals 22B and 22C. The detected voltage of the first battery 200 is detected.

  FIG. 4 shows a state in which the first switch 1A has a short-circuit failure as the assumed failure site. In this case, even if the first switch 1A is controlled to be turned off, the short circuit remains, so that the AD input terminal 22B of the AD converter 22 detects the voltage on the positive side of the first battery 200A.

  If none of the first switches 1A to 1J has a short-circuit fault, the AD converter 22 detects 0V at both of the AD input terminals 22B and 22C.

  That is, when the control unit 60 detects a voltage other than 0 V in a state where the first switch 1 is turned off, the second switch 2 is turned off, the third switch 3 is turned on, and the constant voltage circuit 30 is turned off, It can be determined that there is a possibility that any of the switches 1A to 1J is short-circuited. When detecting a voltage equal to or higher than the predetermined threshold, the control unit 60 may determine that a voltage other than 0 V has been detected.

  In the present embodiment, the diagnosis device 100 executes the diagnosis 1-1 as the first diagnosis, and checks whether the first switches 1A to 1J have a short-circuit failure. This is because if any one of the first switches 1A to 1J is short-circuited, a relatively high voltage is applied to the operational amplifier 21 when the second switch 2 is turned on, and the operational amplifier 21 may be damaged. is there.

  The control unit 60 executes the diagnosis 1-1 before executing the process of turning on the second switch 2, and if it is determined that any of the first switches 1 </ b> A to 1 </ b> J has a short circuit, performs the subsequent diagnosis process. Stop. Thereby, the diagnostic device 100 can reduce the possibility of the failure of the operational amplifier 21 due to the application of a relatively high voltage.

(Diagnosis 1-2)
The diagnosis 1-2 is an open failure diagnosis of the first switches 1A to 1J other than the lowermost first switch 1K. The diagnosis 1-2 will be described with reference to the block diagram shown in FIG. 5 and the timing chart shown in FIG. In FIG. 5, some of the components of the diagnostic apparatus 100 shown in FIG.

  In the diagnosis 1-2, the control unit 60 controls the second switch 2 to be off and the third switch 3 to be on. The control unit 60 controls the constant voltage circuit 30 shown in FIG. 1 to be turned off.

  The control unit 60 turns on / off the first switches 1 connected to both terminals of the first battery 200 in order from a lower potential side to a higher potential side of the first battery 200. That is, the control unit 60 first turns on / off the first switches 1J and 1K in a state where the first switches 1 are all off. Subsequently, the control unit 60 turns on / off the first switches 1G and 1H. The control unit 60 continues this processing until the first switches 1A and 1B are turned on / off.

  The control unit 60 sequentially switches the first switches 1 connected to both terminals of the first battery 200 not from the low potential side to the high potential side but from the high potential side to the low potential side of the first battery 200. It may be turned on / off.

  FIG. 6 shows a timing chart when the control unit 60 turns on / off the first switches 1A and 1B. When turning on the first switches 1A and 1B, the control unit 60 measures the voltages input to the AD input terminals 22B and 22C at predetermined measurement timings t1 and t2. After that, the control unit 60 turns off the first switches 1A and 1B. The control unit 60 may calculate the average value of the voltages measured at t1 and t2 and use the average value as the detected value of the voltage.

  In the example illustrated in FIG. 6, the control unit 60 measures the voltage at two timings t1 and t2, but the measurement timing is not limited to this. The control unit 60 may measure the voltage at one timing, or may measure the voltage at three or more timings. When measuring the voltage at a plurality of timings, the control unit 60 may calculate an average value and use the average value as a detected value of the voltage. The calculation of the number of measurement timings and the calculation of the average value is the same for the diagnosis 2 and subsequent steps.

  At this time, if any one of the first switches 1A to 1J has an open failure, the AD converter 22 turns on the first switch 1 when the first switch 1 having the open failure is turned on. 0V is detected at the corresponding AD input terminal 22B or 22C.

  FIG. 5 shows a state where the first switches 1A and 1B are turned on when the first switch 1A has an open failure as the assumed failure site. In this case, since the first switch 1A is kept open even if it is turned on, the AD input terminal 22B of the AD converter 22 detects 0V. Further, since the first switch 1B is normally turned on, the AD input terminal 22C of the AD converter 22 detects the voltage on the negative electrode side of the first battery 200A.

  The timing chart of FIG. 6 shows two states, that is, a case where the first switch 1A is normal and a case where an open failure has occurred. As shown in FIG. 6, when the first switch 1A is normal, the AD input terminal 22B of the AD converter 22 detects the voltage on the positive side of the first battery 200A. When the first switch 1A has an open failure, the AD input terminal 22B of the AD converter 22 detects 0V.

  That is, when the control unit 60 turns on / off the first switch 1 sequentially in a state where the second switch 2 is turned off, the third switch 3 is turned on, and the constant voltage circuit 30 is turned off, If 0V is detected while any of the first switches 1A to 1J is turned on, it can be determined that there is a possibility that the first switch 1 has an open failure. The control unit 60 may determine that 0 V is detected when detecting a voltage equal to or lower than a predetermined threshold.

[Diagnosis 2]
Diagnosis 2 is an open failure diagnosis of the first switch 1K, which is the lowermost switch of the first switch 1. The diagnosis 2 will be described with reference to the block diagram shown in FIG. 7 and the timing chart shown in FIG. In FIG. 7, some of the components of the diagnostic device 100 shown in FIG.

  In diagnosis 2, the control unit 60 controls the third switch 3 and the constant voltage circuit 30 shown in FIG. Before the start of the diagnosis 2, the control unit 60 turns off all the first switch 1 and the second switch 2.

  FIG. 8 shows a timing chart in the diagnosis 2. The control unit 60 turns on / off the first switches 1J and 1K connected to both terminals of the first battery 200E that is the battery with the lowest potential among the first batteries 200. Thereafter, when the second switch 2 is turned on, the control unit 60 measures the voltage input to the AD input terminal 22A of the AD converter 22 at predetermined measurement timings t1 to t4. After that, the control unit 60 turns off the second switch 2. The control unit 60 may calculate the average value of the voltages measured at t1 to t4 and use the average value as the detected value of the voltage.

  When the control unit 60 turns on the first switches 1J and 1K, when the first switches 1J and 1K are normal, the potential difference between the two terminals of the capacitor 10 reaches the voltage of the first battery 200E as shown in FIG. To rise. Thereafter, even when the control unit 60 turns off the first switches 1J and 1K, the potential difference is maintained between both terminals of the capacitor 10. In this case, after turning on the second switch, the control unit 60 detects a voltage corresponding to the voltage of the first battery 200E at predetermined measurement timings t1 to t4.

  FIG. 7 illustrates a state where the first switch 1K has an open failure as the assumed failure site. In this case, even if the first switches 1J and 1K are turned on, the capacitor 10 is not charged because the first switch 1K remains open, and the potential difference between both terminals of the capacitor 10 is shown in FIG. 0V as shown. In this case, after turning on the second switch, the control unit 60 detects 0 V at predetermined measurement timings t1 to t4.

  Note that the capacitor 10 is not charged even if the first switch 1J but not the first switch 1K has an open failure. However, when the first switch 1J has an open failure, the open failure is detected in the diagnosis 1-2, and the diagnosis processing is stopped at that time. Therefore, when diagnosis 2 is executed and 0V is detected at the predetermined measurement timings t1 to t4, the control unit 60 can determine that the first switch 1K may have an open failure.

  The sequence based on the timing chart shown in FIG. 8 is the same as the sequence when the control unit 60 detects the voltage of the first battery 200 in the normal processing. Therefore, the control unit 60 can execute the diagnosis 2 in the same sequence as the normal voltage detection sequence of the first battery 200.

[Diagnosis 3]
Diagnosis 3 includes the following seven diagnoses.
・ Diagnosis 3-1: Diagnosis of leakage or short-circuit failure of capacitor 10 ・ Diagnosis 3-2: Diagnosis of open failure of second switch 2 ・ Diagnosis 3-3: Diagnosis of stuck output voltage of operational amplifier 21 (0V)
-Diagnosis 3-4: Short-circuit failure diagnosis of the second switch 2A-Diagnosis 3-5: Short-circuit failure diagnosis of the second switch 2B-Diagnosis 3-6: Short-circuit failure diagnosis of the first switch 1K-Diagnosis 3-7: Operational amplifier 21 Diagnosis of output voltage sticking (5V)

(Diagnosis 3-1)
The diagnosis 3-1 diagnoses a leak failure or a short failure of the capacitor 10. The diagnosis 3-1 will be described with reference to the block diagram shown in FIG. 9 and the timing chart shown in FIG. As shown in FIG. 9, the failure diagnosis target of the diagnosis 3-1 is the capacitor 10. In FIG. 9, some of the components of the diagnostic device 100 shown in FIG.

  In the diagnosis 3-1, the control unit 60 controls the first switch 1 to be off. The control unit 60 controls the third switch 3 shown in FIG. 1 to be turned off. Before the start of the diagnosis 3-1, the control unit 60 turns off the constant voltage circuit 30 and the second switch 2.

  FIG. 10 shows a timing chart in the diagnosis 3-1. The control unit 60 outputs a high signal to the control terminal 30A to turn on the constant voltage circuit 30, and turns on the second switch 2. When the constant voltage circuit 30 and the second switch 2 are turned on, the control unit 60 measures the voltage input to the AD input terminal 22A of the AD converter 22 at predetermined measurement timings t1 to t4. Hereinafter, the measurement at the predetermined measurement timings t1 to t4 is also referred to as “measurement 1”.

  After that, the control unit 60 outputs a low signal to the control terminal 30A to turn off the constant voltage circuit 30. When the constant voltage circuit 30 is turned off, the control unit 60 measures the voltage input to the AD input terminal 22A of the AD converter 22 at predetermined measurement timings t5 to t8. Hereinafter, the measurement at the predetermined measurement timings t5 to t8 is also referred to as “measurement 2”.

  The control unit 60 may adjust the conditions of the predetermined measurement timings t1 to t4 and t5 to t8 as much as possible to the conditions of the measurement timing when detecting the voltage of the first battery 200 in the normal processing. For example, when the number of measurements in the normal processing is four and the four measured values are averaged, the control unit 60 performs the measurement four times at the timing of t1 to t4 in the measurement 1 and calculates the four measured values. May be average. Also, the control unit 60 may measure four times in the measurement 2 at timings t5 to t8, and average the measured values of the four times. In addition, the control unit 60 determines, for example, a delay time from turning on the second switch 2 to starting the measurement 2 and a delay time from turning on the second switch 2 in the normal processing to starting the measurement. It may be the same time. As described above, by adjusting the conditions of the measurement timings t1 to t4 and t5 to t8 in the diagnosis 3-1 to the conditions of the measurement timing when detecting the voltage of the first battery 200 in the normal processing as much as possible, the control unit 60 , Measurement 1 and measurement 2 can be performed with small errors. 12, 14, 16, 18, 20, 22, and 24, the measurement timing conditions are also measured when the voltage of the first battery 200 is detected in the normal processing. The timing may be adjusted as much as possible.

  When the control unit 60 turns on the constant voltage circuit 30 and the second switch 2, if the capacitor 10 is normal, the capacitor 10 is charged by the constant voltage supplied from the constant voltage circuit 30. In this case, in measurement 1, the control unit 60 detects a voltage corresponding to the constant voltage supplied by the constant voltage circuit 30. Further, even when the capacitor 10 has a leak failure, the capacitor 10 can be charged by the constant voltage supplied from the constant voltage circuit 30. In this case, in measurement 1, the control unit 60 can detect a voltage corresponding to the constant voltage supplied by the constant voltage circuit 30. Further, when the capacitor 10 has a short-circuit failure, the capacitor 10 is not charged even if a constant voltage is supplied from the constant voltage circuit 30. In this case, in measurement 1, the control unit 60 detects 0V.

  Subsequently, when the control unit 60 turns off the constant voltage circuit 30, if the capacitor 10 is normal, the capacitor 10 maintains the charged state. In this case, in measurement 2, the control unit 60 detects a voltage corresponding to the constant voltage supplied by the constant voltage circuit 30. When the capacitor 10 has a leak failure, the charge charged in the capacitor 10 decreases due to the leak. In this case, in Measurement 2, the control unit 60 detects a voltage lower than the voltage detected in Measurement 1. When the capacitor 10 has a short-circuit failure, in the measurement 2, the control unit 60 continuously detects 0V.

  When the voltage detected in Measurement 1 is 0 V, control unit 60 can determine that capacitor 10 has a possibility of short-circuit failure. The control unit 60 may determine that 0 V is detected when detecting a voltage equal to or lower than a predetermined threshold.

  When the difference obtained by subtracting the voltage detected in Measurement 2 from the voltage detected in Measurement 1 is larger than a predetermined threshold, control unit 60 can determine that capacitor 10 may have leaked. The predetermined threshold value may be set to an appropriate value in consideration of a voltage reading error, noise, and the like.

  As described above, the control unit 60 can determine that there is a possibility that the capacitor 10 has a leak failure. Thereby, the control unit 60 can reduce the possibility of misreading the voltage of the first battery 200 lower in the normal processing due to the leak failure of the capacitor 10 and overcharging the first battery 200.

(Diagnosis 3-2)
The diagnosis 3-2 is an open failure diagnosis of the second switch 2. The diagnosis 3-2 will be described with reference to the block diagram shown in FIG. 11 and the timing chart shown in FIG. As shown in FIG. 11, the failure diagnosis target of the diagnosis 3-2 is the second switches 2A and 2B. In FIG. 11, some of the components of the diagnostic device 100 shown in FIG.

  In diagnosis 3-2, the control unit 60 controls the first switch 1 to be off. The control unit 60 controls the third switch 3 shown in FIG. 1 to be turned off. Before the start of the diagnosis 3-2, the control unit 60 turns off the constant voltage circuit 30 and the second switch 2.

  FIG. 12 shows a timing chart in the diagnosis 3-2. The control unit 60 controls on / off of the constant voltage circuit 30 and on / off of the second switch 2 at the same timing as in the timing chart shown in FIG. The control unit 60 performs the measurement 1 at the same measurement timings t1 to t4 as in the timing chart shown in FIG. The control unit 60 performs the measurement 2 at the same measurement timings t5 to t8 as in the timing chart shown in FIG.

  When the control unit 60 turns on the constant voltage circuit 30 and the second switch 2, when the second switch 2B is normal, the capacitor 10 is charged by the constant voltage supplied from the constant voltage circuit 30. In this state, when the second switch 2A is normal, the control unit 60 can detect a voltage corresponding to the constant voltage supplied by the constant voltage circuit 30 in Measurement 1. Further, even if the constant voltage circuit 30 is turned off, since the capacitor 10 maintains the charged state, the control unit 60 can also detect the voltage corresponding to the constant voltage supplied by the constant voltage circuit 30 in Measurement 2. .

  When the control unit 60 turns on the constant voltage circuit 30 and the second switch 2, if the second switch 2B has an open failure, the capacitor 10 is not charged by the constant voltage circuit 30. In this case, control unit 60 detects 0 V in measurement 1 and measurement 2.

  When the control unit 60 turns on the constant voltage circuit 30 and the second switch 2 and the second switch 2A has an open failure, the voltage of the first node 10A is not applied to the AD input terminal 22A of the AD converter 22. . In this case, the input terminal on the positive side of the operational amplifier 21 is grounded to the ground through a resistance component of about several kilo-ohms due to a wraparound of a peripheral circuit or the like. Is detected.

  If the voltage detected in Measurement 1 and Measurement 2 is 0 V, the control unit 60 can determine that the second switch 2 has a possibility of an open failure. The control unit 60 may determine that 0 V is detected when detecting a voltage equal to or lower than a predetermined threshold.

(Diagnosis 3-3)
The diagnosis 3-3 diagnoses whether the output voltage of the operational amplifier 21 is stuck at 0V. The diagnosis 3-3 will be described with reference to the block diagram shown in FIG. 13 and the timing chart shown in FIG. As illustrated in FIG. 13, the failure diagnosis target of the diagnosis 3-3 is the operational amplifier 21. In FIG. 13, some of the components of the diagnostic device 100 shown in FIG.

  In diagnosis 3-3, the control unit 60 controls the first switch 1 to be off. The control unit 60 controls the third switch 3 shown in FIG. 1 to be turned off. Before the start of the diagnosis 3-3, the control unit 60 turns off the constant voltage circuit 30 and the second switch 2.

  FIG. 14 shows a timing chart of the diagnosis 3-3. The control unit 60 controls on / off of the constant voltage circuit 30 and on / off of the second switch 2 at the same timing as in the timing chart shown in FIG. The control unit 60 performs the measurement 1 at the same measurement timings t1 to t4 as in the timing chart shown in FIG. The control unit 60 performs the measurement 2 at the same measurement timings t5 to t8 as in the timing chart shown in FIG.

  When the control unit 60 turns on the constant voltage circuit 30 and the second switch 2, the capacitor 10 is charged by the constant voltage supplied from the constant voltage circuit 30. In this state, when the operational amplifier 21 is normal, the operational amplifier 21 outputs a voltage corresponding to the constant voltage supplied by the constant voltage circuit 30 to the AD input terminal 22A of the AD converter 22. Therefore, control unit 60 can detect a voltage corresponding to the constant voltage supplied by constant voltage circuit 30 in measurement 1. Further, even if the constant voltage circuit 30 is turned off, since the capacitor 10 maintains the charged state, the control unit 60 can also detect the voltage corresponding to the constant voltage supplied by the constant voltage circuit 30 in Measurement 2. .

  If the output of the operational amplifier 21 is stuck at 0 V, the operational amplifier 21 outputs 0 V even if a voltage corresponding to the constant voltage supplied by the constant voltage circuit 30 is input. Therefore, when the output of the operational amplifier 21 is stuck to 0 V, the control unit 60 detects 0 V in measurement 1 and measurement 2. When the output of the operational amplifier 21 is stuck to 0V, the output of the detection circuit 20 is stuck to 0V.

  When the voltage detected in Measurement 1 and Measurement 2 is 0 V, the control unit 60 can determine that the output of the operational amplifier 21 may be stuck at 0 V. The control unit 60 may determine that 0 V is detected when detecting a voltage equal to or lower than a predetermined threshold.

(Diagnosis 3-4)
The diagnosis 3-4 is a short-circuit failure diagnosis of the second switch 2A. The diagnosis 3-4 will be described with reference to the block diagram shown in FIG. 15 and the timing chart shown in FIG. As shown in FIG. 15, the failure diagnosis target of the diagnosis 3-4 is the second switch 2A. In FIG. 15, some of the components of the diagnostic device 100 shown in FIG.

  In diagnosis 3-4, the control unit 60 controls the first switch 1 to be off. The control unit 60 controls the third switch 3 shown in FIG. 1 to be turned off. Before the start of the diagnosis 3-4, the control unit 60 turns off the constant voltage circuit 30 and the second switch 2.

  FIG. 16 shows a timing chart of the diagnosis 3-4. The control unit 60 controls on / off of the constant voltage circuit 30 and on / off of the second switch 2 at the same timing as in the timing chart shown in FIG. The control unit 60 performs the measurement 1 at the same measurement timings t1 to t4 as in the timing chart shown in FIG. The control unit 60 performs the measurement 2 at the same measurement timings t5 to t8 as in the timing chart shown in FIG.

  When the second switch 2 is turned off, the control unit 60 measures the voltage input to the AD input terminal 22A of the AD converter 22 at predetermined measurement timings t9 to t12. Hereinafter, the measurement at the predetermined measurement timings t9 to t12 is also referred to as “measurement 3”.

  The input terminal on the positive side of the operational amplifier 21 is grounded via a resistance component of about several kilohms due to a wraparound of a peripheral circuit or the like. Therefore, when the control unit 60 turns off the second switch, when the second switch 2A is normal, the input voltage of the operational amplifier 21 gradually decreases due to the current leaking through the resistance component. In this case, the control unit 60 detects a voltage smaller than the voltage detected in the measurement 2 in the measurement 3.

  If the second switch 2A has a short-circuit fault, the second switch 2A remains short-circuited even if the control unit 60 controls to turn off the second switch 2. In this case, the input voltage of the operational amplifier 21 does not change even if the control unit 60 controls to turn off the second switch 2. Therefore, control unit 60 detects a voltage equivalent to the voltage detected in measurement 2 in measurement 3.

  When the difference obtained by subtracting the voltage detected by measurement 3 from the voltage detected by measurement 1 or 2 is zero, control unit 60 can determine that second switch 2A may have a short-circuit failure. The control unit 60 may determine that the difference is zero when the difference obtained by subtracting the voltage detected in Measurement 3 from the voltage detected in Measurement 1 or Measurement 2 is equal to or smaller than a predetermined threshold.

(Diagnosis 3-5)
The diagnosis 3-5 is a short failure diagnosis of the second switch 2B. The diagnosis 3-5 will be described with reference to the block diagram shown in FIG. 17 and the timing chart shown in FIG. As shown in FIG. 17, the failure diagnosis target of the diagnosis 3-5 is the second switch 2B. In FIG. 17, some of the components of the diagnostic device 100 shown in FIG.

  In diagnosis 3-5, the control unit 60 controls the first switch 1 to be off. The control unit 60 controls the third switch 3 shown in FIG. 1 to be turned off. Before the start of the diagnosis 3-5, the control unit 60 turns off the constant voltage circuit 30 and the second switch 2.

  FIG. 18 shows a timing chart of the diagnosis 3-5. The control unit 60 outputs a high signal to the control terminal 30A to turn on the constant voltage circuit 30, and after a predetermined time elapses, outputs a low signal to the control terminal 30A to turn off the constant voltage circuit 30. The control unit 60 turns off the constant voltage circuit 30, turns on the second switch 2, and then turns off the second switch 2. When the second switch 2 is turned on, the control unit 60 measures the voltage input to the AD input terminal 22A of the AD converter 22 at predetermined measurement timings t13 to t16. Hereinafter, the measurement at the predetermined measurement timings t13 to t16 is also referred to as “measurement 4”.

  When the control unit 60 turns on the constant voltage circuit 30 with the second switch 2 turned off, the capacitor 10 is not charged. This is because when the second switch 2B is normal, the second node 10B is not grounded. Therefore, after that, when the control unit 60 turns off the constant voltage circuit 30 and then turns on the second switch 2, the control unit 60 detects 0V.

  When the second switch 2B has a short-circuit failure, when the control unit 60 turns on the constant voltage circuit 30 with the second switch 2 turned off, the capacitor 10 is charged. This is because when the second switch 2B has a short-circuit fault, the second node 10B is grounded. Therefore, after that, when the control unit 60 turns off the constant voltage circuit 30 and then turns on the second switch 2, the control unit 60 detects a voltage corresponding to the constant voltage supplied by the constant voltage circuit 30.

  When the voltage detected in Measurement 4 is not 0 V, control unit 60 can determine that second switch 2B may have a short-circuit failure. When detecting a voltage equal to or higher than the predetermined threshold, the control unit 60 may determine that a voltage other than 0 V has been detected.

(Diagnosis 3-6)
The diagnosis 3-6 is a short-circuit failure diagnosis of the first switch 1K, which is the lowermost switch of the first switch 1. The diagnosis 3-6 will be described with reference to the block diagram shown in FIG. 19 and the timing chart shown in FIG. As shown in FIG. 19, the failure diagnosis target of the diagnosis 3-6 is the first switch 1K. In FIG. 19, some of the components of the diagnostic device 100 shown in FIG.

  In diagnosis 3-6, the control unit 60 controls the first switch 1 to be off. The control unit 60 controls the third switch 3 shown in FIG. 1 to be turned off. Before the start of the diagnosis 3-6, the control unit 60 turns off the constant voltage circuit 30 and the second switch 2.

  FIG. 20 shows a timing chart in the diagnosis 3-6. The control unit 60 controls on / off of the constant voltage circuit 30 and on / off of the second switch 2 at the same timing as in the timing chart shown in FIG. The control unit 60 performs the measurement 4 at the same measurement timings t13 to t16 as in the timing chart shown in FIG.

  When the control unit 60 turns on the constant voltage circuit 30 with the second switch 2 turned off, the capacitor 10 is not charged. This is because when the first switch 1K is normal, the second node 10B is not grounded. Therefore, after that, when the control unit 60 turns off the constant voltage circuit 30 and then turns on the second switch 2, the control unit 60 detects 0V.

  When the first switch 1K has a short-circuit failure, when the control unit 60 turns on the constant voltage circuit 30 with the second switch 2 turned off, the capacitor 10 is charged. This is because when the first switch 1K is short-circuited, the second node 10B is grounded. Therefore, after that, when the control unit 60 turns off the constant voltage circuit 30 and then turns on the second switch 2, the control unit 60 detects a voltage corresponding to the constant voltage supplied by the constant voltage circuit 30.

  When the voltage detected in measurement 4 is not 0 V, control unit 60 can determine that first switch 1K may have a short-circuit failure. When detecting a voltage equal to or higher than the predetermined threshold, the control unit 60 may determine that a voltage other than 0 V has been detected.

(Diagnosis 3-7)
The diagnosis 3-7 diagnoses whether the output voltage of the operational amplifier 21 is stuck to the power supply voltage (for example, 5V). The diagnosis 3-7 will be described with reference to the block diagram shown in FIG. 21 and the timing chart shown in FIG. As shown in FIG. 21, the failure diagnosis target of the diagnosis 3-7 is the operational amplifier 21. In FIG. 21, some of the components of the diagnostic device 100 shown in FIG.

  In diagnosis 3-7, the control unit 60 controls the first switch 1 to be off. The control unit 60 controls the third switch 3 shown in FIG. 1 to be turned off.

  FIG. 22 shows a timing chart of the diagnosis 3-7. The control unit 60 measures the voltage input to the AD input terminal 22A of the AD converter 22 at a predetermined measurement timing t17 to t20 before turning on the constant voltage circuit 30 and the second switch 2. Hereinafter, the measurement at the predetermined measurement timings t17 to t20 is also referred to as “measurement 5”.

  Before the control unit 60 turns on the constant voltage circuit 30 and the second switch 2, the capacitor 10 is not charged. In this state, when the operational amplifier 21 is normal, the operational amplifier 21 outputs 0V to the AD input terminal 22A of the AD converter 22. Therefore, control unit 60 can detect 0 V in measurement 5.

  When the output of the operational amplifier 21 is stuck to the power supply voltage (for example, 5 V), the operational amplifier 21 outputs 5 V even if 0 V is input to the operational amplifier 21. Therefore, when the output of the operational amplifier 21 is stuck at 5 V, the control unit 60 detects 5 V in measurement 5. When the output of the operational amplifier 21 sticks to 5V, the output of the detection circuit 20 also sticks to 5V.

  When the voltage detected in the measurement 5 is the power supply voltage of the operational amplifier 21 (for example, 5 V), the control unit 60 can determine that the output of the operational amplifier 21 may be stuck at 5 V. The controller 60 may determine that 5 V has been detected when detecting a voltage whose difference from 5 V is equal to or less than a predetermined threshold.

[Diagnosis 4]
Diagnosis 4 is a failure diagnosis of the operational amplifier 21. The diagnosis 4 will be described with reference to the block diagram shown in FIG. 23 and the timing chart shown in FIG. In FIG. 23, some of the components of the diagnostic device 100 shown in FIG.

  In diagnosis 4, the control unit 60 controls the third switch 3 and the constant voltage circuit 30 shown in FIG. Before the start of the diagnosis 4, the control unit 60 has turned off all of the first switch 1 and the second switch 2.

  FIG. 24 shows a timing chart in the diagnosis 4. The control unit 60 outputs a high signal to the control terminal 30A to turn on the constant voltage circuit 30, and turns on the second switch 2. When the constant voltage circuit 30 and the second switch 2 are turned on, the control unit 60 measures the voltage input to the AD input terminal 22A of the AD converter 22 at predetermined measurement timings t21 to t24. In the diagnosis 4, when the constant voltage circuit 30 and the second switch 2 are turned on, the control unit 60 turns on the voltage input to the AD input terminal of the AD converter 52 of the sub detection circuit 50 at the measurement timings t21 to t24. Also measure. Hereinafter, the measurement at the predetermined measurement timings t21 to t24 is also referred to as “measurement 6”.

  When the control unit 60 turns on the constant voltage circuit 30 and the second switch 2, the capacitor 10 is charged by the constant voltage supplied from the constant voltage circuit 30. In this case, in measurement 6, when the operational amplifier 21 is normal, the control unit 60 detects a voltage corresponding to the constant voltage supplied by the constant voltage circuit 30 from both the detection circuit 20 and the sub-detection circuit 50. When there is an abnormality in the operational amplifier 21, the control unit 60 detects different voltages from the detection circuit 20 and the sub-detection circuit 50 in the measurement 6.

  If the difference between the voltage obtained from the detection circuit 20 and the voltage obtained from the sub-detection circuit 50 in measurement 6 is larger than a predetermined threshold, the control unit 60 determines that the operational amplifier 21 may be faulty. Can be determined.

[Procedure of diagnosis 3 and diagnosis 4]
An example of the detailed procedure of step S3 (diagnosis 3) and step S4 (diagnosis 4) shown in FIG. 3 will be described with reference to the flowcharts shown in FIGS.

  The control unit 60 of the diagnostic device 100 starts the flow shown in FIGS. 25 to 27 from a state in which the first switch 1, the second switch 2, the third switch 3, and the constant voltage circuit 30 are controlled to be off. .

  The control unit 60 turns on the second switch 2 (step S101) and turns on the constant voltage circuit 30 (step S102), for example, as in the timing chart shown in FIG. The control unit 60 may execute Step S101 and Step S102 simultaneously. The control unit 60 may execute step S102 before step S101.

  The control unit 60 executes the measurement 1 (step S103). The control unit 60 turns off the constant voltage circuit 30 (Step S104). The control unit 60 performs the measurement 2 (step S105).

  The control unit 60 determines whether a failure of the diagnosis 3-1, the diagnosis 3-2, or the diagnosis 3-3 has been detected based on the results of the measurement 1 and the measurement 2 (step S106).

When the voltage detected in Measurement 1 is 0 V, control unit 60 can determine that there is a possibility of any of the following failures. The control unit 60 may determine that 0 V is detected when detecting a voltage equal to or lower than a predetermined threshold.
・ Short fault of capacitor 10 (diagnosis 3-1)
Open failure of the second switch 2 (diagnosis 3-2)
-Sticking the output of the operational amplifier 21 to 0V (Diagnosis 3-3)

  If the difference obtained by subtracting the voltage detected in measurement 2 from the voltage detected in measurement 1 is larger than a predetermined threshold, control unit 60 can determine that capacitor 10 may have leaked (diagnosis 3- 1).

  When the failure of the diagnosis 3-1, the diagnosis 3-2, or the diagnosis 3-3 is detected (Yes in step S106), the control unit 60 sets a failure flag (step S107) and ends the diagnosis processing.

  When a failure of the diagnosis 3-1, the diagnosis 3-2, or the diagnosis 3-3 is not detected (No in step S106), the control unit 60 proceeds to step S108.

  The control unit 60 turns off the second switch 2 (step S108) and executes measurement 3 (step S109), for example, as shown in the timing chart of FIG.

  The control unit 60 determines whether a failure in the diagnosis 3-4 has been detected based on the results of the measurements 1 to 3 (step S110).

  When the difference obtained by subtracting the voltage detected in Measurement 3 from the voltage detected in Measurement 1 or Measurement 2 is zero, the control unit 60 may determine that the second switch 2A may have a short circuit failure (Diagnosis 3 -4). The control unit 60 may determine that the difference is zero when the difference obtained by subtracting the voltage detected in Measurement 3 from the voltage detected in Measurement 1 or Measurement 2 is equal to or smaller than a predetermined threshold.

  When the failure of the diagnosis 3-4 is detected (Yes in Step S110), the control unit 60 sets a failure flag (Step S111) and ends the diagnosis processing.

  When the failure of the diagnosis 3-4 is not detected (No in Step S110), the control unit 60 proceeds to Step S112.

  The control unit 60 turns on the fourth switch 4 to discharge the capacitor 10 (Step S112).

  The control unit 60 turns on the constant voltage circuit 30 and then turns off (step S113) and turns on the second switch 2 (step S114), as shown in the timing chart of FIG. 18, for example. The control unit 60 executes the measurement 4 (step S115).

  The control unit 60 determines whether a failure of the diagnosis 3-5 or the diagnosis 3-6 has been detected based on the result of the measurement 4 (step S116).

When the voltage detected in Measurement 4 is not 0 V, control unit 60 can determine that there is a possibility of any of the following failures. When detecting a voltage equal to or higher than the predetermined threshold, the control unit 60 may determine that a voltage other than 0 V has been detected.
-Short circuit failure of the second switch 2B (diagnosis 3-5)
・ Short fault of the first switch 1K (Diagnosis 3-6)

  When the failure of the diagnosis 3-5 or the diagnosis 3-6 is detected (Yes in step S116), the control unit 60 sets a failure flag (step S117) and ends the diagnosis processing.

  When the failure of the diagnosis 3-5 or the diagnosis 3-6 is not detected (No in Step S116), the control unit 60 proceeds to Step S118.

  The control unit 60 turns off the second switch 2 (Step S118).

  The control unit 60 turns on the fourth switch 4 to discharge the capacitor 10 (Step S119). When the failure of the diagnosis 3-5 or the diagnosis 3-6 has not occurred, the capacitor 10 is not charged, and thus the step S119 can be omitted.

  The control unit 60 performs the measurement 5 in a state where the constant voltage circuit 30 and the second switch 2 are off, for example, as in a timing chart illustrated in FIG. 22 (step S120).

  The control unit 60 turns on the constant voltage circuit 30 (step S121) and turns on the second switch 2 (step S122), for example, as in the timing chart shown in FIG. The control unit 60 may execute step S121 and step S122 at the same time. The control unit 60 may execute step S122 before step S121.

  The control unit 60 executes the measurement 6 (step S123).

  The control unit 60 determines whether a failure of the diagnosis 3-7 or the diagnosis 4 has been detected based on the results of the measurement 5 and the measurement 6 (step S124).

  When the voltage detected in the measurement 5 is the power supply voltage of the operational amplifier 21 (for example, 5 V), the control unit 60 can determine that the output of the operational amplifier 21 may be stuck at 5 V (diagnosis 3-7). . The controller 60 may determine that 5 V has been detected when detecting a voltage whose difference from 5 V is equal to or less than a predetermined threshold.

  If the difference between the voltage obtained from the detection circuit 20 and the voltage obtained from the sub-detection circuit 50 in measurement 6 is larger than a predetermined threshold, the control unit 60 determines that the operational amplifier 21 may be faulty. It can be determined (diagnosis 4).

  When the failure of diagnosis 3-7 or diagnosis 4 is detected (Yes in step S124), the control unit 60 sets a failure flag (step S125) and ends the diagnosis processing.

  When the failure of the diagnosis 3-7 or the diagnosis 4 is not detected (No in Step S124), the control unit 60 ends the diagnosis processing.

  The control unit 60 may control the subsequent use of the first battery 200 when setting the failure flag in step S107, step S111, step S117, or step S125 to end the diagnostic processing.

  The timing of the failure determination in step S106, step S110, step S116, and step S124 is an example, and is not limited to this.

For example, the following failure determination in step S106 may be performed at the stage when measurement 1 is performed in step S103.
・ Short fault of capacitor 10 (diagnosis 3-1)
Open failure of the second switch 2 (diagnosis 3-2)
-Sticking the output of the operational amplifier 21 to 0V (Diagnosis 3-3)

  For example, the failure determination in step S106 may be performed together with the failure determination in step S110 after performing measurement 3 in step S109.

  For example, the failure determination of the diagnosis 3-7 in step S124 may be performed at the stage when the measurement 5 is performed in step S120.

  In the present embodiment, the detection circuit 20 has been described as detecting the potential difference between both terminals of the capacitor 10, but the detection circuit 20 may detect a discharge current from the capacitor 10.

  According to the diagnostic device 100 according to the present embodiment, the diagnostic device 100 can apply a voltage to the capacitor 10 from the second battery 300 different from the first battery 200. Further, the detection circuit 20 detects the potential difference or the discharge current after the control unit 60 turns on the PNP transistor 32 and applies a voltage from the second battery 300 to the capacitor 10. Then, the control unit 60 diagnoses at least one of the capacitor 10, the first switch 1K, and the second switch 2. Accordingly, the diagnostic device 100 according to the present embodiment can diagnose the states of the capacitor 10, the first switch 1K, and the second switch 2 without depending on the first battery 200 to be detected.

  Further, according to the diagnostic apparatus 100 according to the present embodiment, a constant voltage can be supplied from the constant voltage circuit 30 to the capacitor 10 at the time of failure diagnosis, so that a threshold value for determining whether or not there is a failure can be easily set. Can.

  One embodiment according to the present disclosure has been described based on the drawings and examples, but it should be noted that those skilled in the art can easily make various changes or modifications based on the present disclosure. Therefore, it should be noted that these variations or modifications are included in the scope of the present disclosure. For example, the functions and the like included in each means can be rearranged so as not to be logically inconsistent, and a plurality of means and the like can be combined into one or divided.

Reference Signs List 100 Diagnostic device 1, 1A to 1K First switch 2, 2A, 2B Second switch 3, 3A, 3B Third switch 4 Fourth switch 10 Capacitor (flying capacitor)
10A first node 10B second node 11 resistor 20 detection circuit 21 operational amplifier 22 AD converter 22A to 22C AD input terminal 30 constant voltage circuit 30A control terminal 30B output terminal 30C power supply terminal 31 NPN transistor 32 PNP transistor 33 capacitor 34, 35, 36 , 37, 38 resistance 40 capacitor voltage detection circuit 41, 42, 43, 44 resistance 50 sub-detection circuit 51 operational amplifier 52 AD converter 60 control unit 70 storage unit 200, 200A to 200E first battery 300 second battery 400 voltage conversion circuit

Claims (12)

A capacitor connectable in parallel to each first battery of the plurality of first batteries connected in series;
A plurality of first switches for switching a connection state between the plurality of first batteries and the capacitor;
A detection circuit that detects a potential difference between both terminals of the capacitor, or detects a discharge current from the capacitor,
A second switch for switching a connection state between the capacitor and the detection circuit;
A changeover switch for switching a connection state between the second battery different from the first battery and the capacitor;
A control unit that controls the first switch, the second switch, and the changeover switch;
The capacitor, a lowermost first switch connected to the ground among the plurality of first switches, and a diagnostic unit that diagnoses at least one of the second switch,
After the control unit turns on the changeover switch and applies a voltage from the second battery to the capacitor, the detection circuit detects a potential difference or a discharge current,
The diagnostic device, wherein the diagnostic unit diagnoses at least one of the capacitor, the lowermost first switch, and the second switch. The diagnostic device according to claim 1,
A diagnostic apparatus further comprising a constant voltage circuit that generates a constant voltage from the second battery and outputs a constant voltage to the capacitor via the changeover switch. The diagnostic device according to claim 2,
The diagnostic device, wherein the constant voltage is smaller than a maximum voltage that can be supplied by the plurality of first batteries connected in series. The diagnostic device according to claim 2 or 3,
The diagnostic device, wherein the constant voltage is higher than a maximum voltage that can be supplied by the first battery. The diagnostic device according to any one of claims 1 to 4,
The diagnostic device, wherein the second battery is a lead storage battery. The diagnostic device according to claim 2,
The control unit outputs the constant voltage to the capacitor, and in a state where the second switch is turned on, the diagnostic unit, based on a potential difference between both terminals of the capacitor detected by the detection circuit, A diagnostic device for diagnosing a short-circuit failure of a capacitor, an open failure of the second switch, or a possibility that the output of the detection circuit may stick to 0V. The diagnostic device according to claim 6,
After the control unit turns off the constant voltage, the diagnosis unit further determines whether the capacitor may be leaking based on the potential difference between the two terminals of the capacitor detected by the detection circuit. A diagnostic device that diagnoses. The diagnostic device according to claim 6 or 7,
The second switch includes an upper second switch that switches a connection state between one end of the capacitor and the detection circuit, and a lower second switch that switches a connection state between the other end of the capacitor and ground,
After the control unit turns off the constant voltage and then turns off the second switch, the diagnosis unit further sets the upper and lower terminals based on a potential difference between the two terminals of the capacitor detected by the detection circuit. A diagnostic device for diagnosing the possibility of a two-switch short failure. The diagnostic device according to claim 8,
After the control unit outputs the constant voltage to the capacitor, turns off the constant voltage, and then turns on the second switch. Then, the diagnostic unit determines whether or not the two terminals of the capacitor have been detected by the detection circuit. A diagnostic device that diagnoses whether there is a possibility of a short-circuit failure of the lower second switch or a short-circuit failure of the lowermost first switch based on a potential difference. The diagnostic device according to any one of claims 2 to 4 and 6 to 9 ,
In the state where the second switch is off, before outputting the constant voltage to the capacitor, the diagnosis unit outputs the output of the detection circuit based on a potential difference between both terminals of the capacitor detected by the detection circuit. Diagnostic device that diagnoses the possibility of sticking to the power supply voltage. The diagnostic device according to any one of claims 2 to 4 and 6 to 10 ,
The control unit outputs the constant voltage to the capacitor, and in a state where the second switch is turned on, the diagnostic unit, based on a potential difference between both terminals of the capacitor detected by the detection circuit, A diagnostic device that diagnoses whether the detection circuit may have failed. A capacitor that can be connected in parallel to each first battery of the plurality of first batteries connected in series, a plurality of first switches that switch a connection state between the plurality of first batteries and the capacitor, and both terminals of the capacitor A detection circuit that detects a potential difference between the two or a discharge current from the capacitor, a second switch that switches a connection state between the capacitor and the detection circuit, and a second battery that is different from the first battery. A changeover switch for switching a connection state with the capacitor, and a diagnostic method in a diagnostic device including:
Turning on the switch, applying a voltage from the second battery to the capacitor, the detection circuit detects a potential difference or a discharge current,
A diagnostic method comprising: diagnosing at least one of the capacitor, a lowermost first switch connected to ground among the plurality of first switches, and the second switch.

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